A signature technique using an algorithm of public-key cryptosystems may be used for device authentication or electronic message signature authentication. For example, a Rivest Shamir Adleman (RSA) algorithm is used for an internet encoding and authenticating method of performing encoding and decoding by creating a public key and a private key as a set. The private key is stored in a device, and the public key is transmitted and stored in a counterpart device of, for example, a certification authority (CA).
Because a signature may be forged when a private key using the algorithm of public-key cryptosystems such as the RSA algorithm is exposed/leaked, the private key may be targeted by a security attack, for example, a side channel attack. Among types of side channel attacks, a differential power analysis (DPA) attack that statistically analyzes and collects a large volume of data may be powerful.
A physically unclonable function (PUF) may provide an unpredictable digital value. Individual PUFs may provide different digital values, even though the individual PUFs are manufactured through the same exact manufacturing process. The PUF may be referred to as a “physical one-way function (POWF)” that is practically unclonable.
The above mentioned unclonable aspect of the PUF may be used to generate an identifier of a device for security and/or authentication. For example, the PUF may be used to provide a unique key to distinguish devices from one another.
Korean Patent Registration No. 10-1139630 (hereinafter, referred to as “'630 patent”) proposes a method of implementing a PUF. The '630 patent discloses a method of determining based on probability whether an inter-layer contact or a via is generated between conductive layers of a semiconductor, based on a semiconductor process variation.